Page:The Zoologist, 3rd series, vol 1 (1877).djvu/136

110 able communication by Dr. Francis Day, a well-known authority on all that relates to the fishes of the region in question. He laid down the following propositions, and by facts endeavoured to substantiate them:—(1) That there are fishes in Asia which normally respire atmospheric air direct; (2) that these fishes possess respiratory organs having a lung-like function, and which is distinct from the gills; (3) that they are essentially amphibious, inasmuch as the accessory organs receive venous and return arterial blood into the general circulation without passing through the branchiæ or gills; (4) that this accessory respiratory sac is certainly not homologous with the swim-bladder of fishes, but is most probably so with the respiratory sac of amphibious reptiles. He gave numerous instances of forms which respire air direct, and can live for long periods after their removal from water, being but little affected by a bandage being placed round their gills preventing the use of these organs. He observed that in the Saccobranchus both a respiratory sac and a swim-bladder co-exist—the one along the muscles of the back, the other more or less enclosed in bone but possessing a pneumatic duct. The migrations of fishes at the commencement of monsoons are due to two causes—breeding purposes and a search for food. The aerial respiration of certain amphibious fishes he regards as a provision to enable those forms to migrate through moist grass and muddy channels. As soon as the rains set in and vegetation starts afresh, insects, worms, land mollusks and other invertebrates are revivified, and with this the fish restlessly seek change of locality and diet, in their search for quarters where these abound. As regards the sudden appearance of fish supposed to have fallen from the clouds, these are occasionally met with in a semi-decomposed state, and are doubtless carried by whirlwinds and storms from shallow waters into mid-air, whence they fall again in most unlooked-for situations. In other innumerable instances the apparently inexplicable profusion of fish in moist spots away from water is accounted for by the remarkable retention of vitality possessed by the mud-loving species, which emerge from torpidity into active life as soon as the waters return.

The Jelly-fish have lately been made the subject of study by Mr. J.G. Romanes, who read a second notice "On Varieties and Monstrous Forms of Medusæ." He expressed surprise that among the group of Jelly-fish, at least the naked-eyed groups, with their low grade of organization and proneness to exhibit phenomena of budding or germination, examples of monstrous and misshapen forms are comparatively rare. In those cases met with by him, especially in the common Aurelia aurita, the deviations from the normal type always occurred in a multiplication or suppression (i.e., abortion) of entire segments. This affects the segments of the umbrella in a remarkably symmetrical manner, whilst the ovaries and manubrium, to a certain extent, may or may not be implicated.